The present invention relates to a seal assembly for sealing the shaft in an opening in a stationary housing. More particularly, the invention relates to a seal assembly which provides a grease seal which permits effective purging during the operation and lubrication of the bearings while minimizing the ingress of moisture and foreign particulate matter which would cause excessive wear on the operating parts of the bearing and shaft.
One prior art bearing seal is disclosed in U.S. Pat. No. 4,348,067, the disclosure of which is hereby incorporated in full by reference. The '067 patent discloses a sealing structure for a bearing shaft which consists of the combination of an inner labyrinth seal, an outer V-ring seal, and a sleeve which fits snugly on the shaft and forms a part of the labyrinth seal and supports the V-ring seal. When the sleeve is assembled in place on the shaft in the bearing housing, the lip of the V-ring seats on an annular radially inwardly extending sealing surface on the housing externally of the labyrinth seal. The seal assembly disclosed in the '067 patent functions very effectively, but it may be difficult to properly assemble the various parts of the bearing seal disclosed in the '067 patent when the pillow block assembly is located in a place with difficult access. For example, in some situations, the lip of the V-ring seal may project into the housing joint between the upper and lower housing assemblies when the assembly is being placed in the pillow block. In such a situation, it would become pinched between the upper and lower housing thereby not operating effectively. In addition, in the '067 patent, the V-ring lip engages the housing face which has a joint gap between the cap and base.